An Instinct too many
by TemptationMagic
Summary: Tsubaki decided that it was about time for the Asahina family to celebrate Halloween outside of their residence, and convinced all of them to go to a haunted mansion in the outskirts of town for the fun of it, but misfortune had stumbled upon the brothers, and they ended up in another manor to avoid the rain for the night. Little do they know, their bodies slowly begin to change...
1. Chapter 1

**A/N: Just as a note, the brothers might be OOC due to the odd situation they're put in, and since this is my first ever published brothers conflict fanfic, there are bound to be inaccuracies, in which I apologize in advance for. Also, this is based on the nico nico Hetalia fangame Licantropo, so credit for the story goes to** **惟刀** **維月** **(Itou Itsuki) from nico nico and the English translation to Autumnflower1991 on dA!**

 **Chapter 1**

"Hey, hurry up you guys! The sun's gonna rise before we even get there if you keep walking at that pace!"

Tsubaki's voice roared from over the hill, echoing into the far distances of the dark night sky littered with glittering stars and windy fields, with leaves of various shades of red and orange that were blowing around and about. Lamps brightly lit up the stone paved path, all lined up in a single file that stretched from end to end. Trees towered over the road, its shadows threatening to engulf whatever glimpse of light was left, accompanied by the shrubs that were acting as a barrier against the outgrowing trees.

Several men were tirelessly making their way towards the source of the booming voice, their chests heavily heaving and their postures almost limping. Some of them would even potentially scare others with the way they're walking and their costumes in the dark.

"Come on Maa-kun! What if Tsukkun is right?" Wataru shouted, his hands covering his mouth to form a sort of megaphone.

"T…That's not possible…it's only 7 pm…unless Tsubaki didn't check…the distance between our apartment…and this so-called haunted mansion…" Ukyo said breathlessly, pausing for a minute to regain some air in his lungs.

Fuuto groaned and threw his arms up in the air, swinging his hooked hand around and his expression contorted in disgust, "It feels like we've been walking for hours on end! Why couldn't we just use our cars or something?!"

"It's more fun as a family this way! Plus, I think we're pretty close to the place!" Tsubaki pointed his lantern towards the path that seemingly went on forever ahead, causing many groans to erupt.

"Aaah!" Yuusuke cried out in rage, "What were we thinking listening to you?! I can't believe you even managed to convince every single one of us to come along to this…this thing!"

"Getting angry and wanting to kill Tsubaki would only make this longer; let's just hurry up and get this over with so we can go back home." Natsume huffed, wiping sweat off his brow with his large, grey and furry wolf paws.

Mumbles of exasperation and whines echoed within the group; one could swear they heard a muffled sob somewhere. Nonetheless, the brothers continue on, eventually reaching the top of the grassy hill and dragging themselves forward onto the pavement ahead.

Trailing down the road, the flora began to seemingly grow thicker, almost to a point where it was as if a dense fog hung over the boys. This caused panic in some of them to arise, what with Masaomi immediately using his body as a human shield for Wataru, whom was protesting against the protection. Seemingly unfamiliar creatures roamed about as well, its sounds ranging from soft chirps to low growls, and eyes that were piercing its gaze onto the only human men that were trekking through the pathway, attempting to send cold shivers down their spines.

"Tsuba-chan…don't you think we should turn back?" Kaname stopped in his tracks. "I'm sure we can all live without having to see this mansion; maybe we can just have our own tiny Halloween party instead."

Tsubaki had stopped as well, his shoulders slumped. He sighed; perhaps they were getting further away from the mansion instead, having run around in circles for nothing. It was only a matter of time until everyone would end up walking a full marathon until sunrise, and still end up empty-handed; it was the last thing Tsubaki wanted, especially when all of the brothers were finally able to get some time off and get together as a family.

But just as Tsubaki was about to declare his defeat, a flash of white blinded all of the brothers for a split second, and thunder roared monstrously, startling everyone. The sky then began to pour heavily, drenching everything and everyone; its droplets harshly echoing against the stone pavement.

"See, you idiot seiyuu?! All the more reason to go back home!" Fuuto growled, attempting to cover himself with both of his hands over his head.

"We've been walking for quite a bit though...I don't think we'll be able to make it back home safely in this kind of weather." Azusa said, covering himself as well.

"There's…a mansion over there— is it the one Tsubaki-niisan talked about?" Louis gestured his pitchfork towards the monstrous residence that was just a couple of steps away from where they were. Everyone took a good second to look at it, then back at Tsubaki.

"It's…not, the one I wanted all of us to visit had this really cool pumpkin patch in the front yard." Tsubaki's expression was laced with confusion.

"Well, whatever mansion that is, let's just go and see if we can stay there for the night—hopefully the owners are kind enough to let us in." Masaomi ushered all of his brothers to the large home ahead, to which they all wordlessly agreed and followed.

It wasn't long after they trudged through the damp forest-like area out into a crossroad, taking a turn to the left, and faced the intimidating manor that stood proud and tall before them.

It had a Victorian charm to it, protected by black-colored gates that were in the shape of spears, lined up neatly in a row encircling the residence. Weathered oak made up the bulk of the mansion, complimented with its black tiled roof with odd small spears as its accessory. Arched windows were scattered about, visibly dusty, yet a glimpse of light could be seen from the inside. Although, light was scarce on the front porch. Hanging rustic lamps swung back and forth in a rough motion.

The boys took a step forward onto the porch, several startled by the creaking floorboards. The two eldest brothers stood at the very front of the massive door, with both of them exchanging hesitant glances; the former being the one to knock using the large, golden door ring with a lion head on it.

...No response.

Masaomi took the ring in his palm again, and knocked even harder against the door.

…Still nothing.

"Maybe the owners are not home?" Iori suggested. Everyone looked at one another in confusion, mixed in with frustration.

"But the lights are on inside!" Subaru argued in irritation. "Can't we just go inside? We can't stay here all night long!" He was practically shivering from the cold winds blowing about and the rain water soaking into his shirt.

"But we can't just barge into someone's home." Azusa countered, his entire body shaking as well.

"Subaru has a point though—I'm sure the thirteen of us won't make _that_ big of a mess while we're inside. Plus, we're only staying for the night and nothing more." Hikaru knew that wasn't exactly the truth, but he was getting slightly desperate himself as well, considering he only wore a V-neck sleeveless dress with maroon heels; his only way of warming himself being his snake-hair extensions.

"Well…it'd be troublesome if all of us ended up with a cold the next morning, so I suppose it's alright just for tonight." Masaomi proceeded to push the door open, along with Ukyo whom aided him in doing so.

Behind the doors revealed a grand foyer; a large golden chandelier lit with small candles hanging from above. The stairs were covered in a velvet carpet with golden accents, greeting the brothers with wide open wooden floorboards. Paintings of various items and people and candles decorated the walls that were colored in a warm shade of brown.

"…This is oddly nice for a mansion that looked like it was crumbling to pieces…" Natsume mused, taking in the astonishing interior design with his mouth slightly open as he twisted and turned his head around.

"You tell me…" Tsubaki was just as amazed, kneeling down to get a closer look at a tiny, yet carefully sculpted statue of a female made out of pure marble as one of the displays by the left side of the stairs.

"Alright, alright we get how _great_ this place looks—can we just go and find some rooms to sleep in? I'm exhausted, and as an idol I need my beauty rest." Fuuto grumbled aloud, rolling his eyes as he tapped his foot against the floor impatiently.

"Fuuto's right," Ukyo came walking down from the stairs, surprising everyone in the room, "Staying up late would also cause us to have a cold, so we all have to get some sleep right now."

"E-eh? Where did you- how did you- " Kaname started, but was cut off by Ukyo.

"You simply didn't pay enough attention." The blonde brother pushed his glasses up to the bridge of his nose, letting out a small sigh, "Anyways, it seems there are enough rooms for all of us to stay in, each having two beds. I will be the one to assign whom you get to sleep with, and _no_ complaints, because I'm very sure we're all too tired and sore at this point to fight over which rooms we want and whom we want to sleep with."

Everyone exchanged glances, signaling Ukyo that they all agreed—or rather, didn't want to push his buttons any further.

Ukyo then proceeded, "Alright. So, all the rooms I will mention are from the far left end of the hallway on the second floor all the way to the right end. Masaomi and Wataru will be in room 201, Kaname and Yuusuke will be in room 202, Hikaru and Louis will be in room 203, the triplets will be in room 204, Iori and Fuuto will be in room 205 and Subaru and I will be in room 206. Is that clear?"

Everyone nodded, and walked sluggishly towards their assigned rooms—except for Ukyo. He made sure all of his brothers did as they were told, so he stayed behind for a bit. After waiting for a few minutes after they went into their rooms, he proceeded to walk towards to his own.

Opening the door, the room was rather cozy, warmly lit by shades of yellow light reflected by maroon walls. Twin beds were laid in the middle of the space, clean, white sheets and soft pillows in each of them. Ukyo had noticed Subaru already took the accessories of his Halloween costume off, and already in bed, but was startled by the elder brother that opened the door.

"Sorry." Ukyo whispered, feeling bad for waking his already exhausted brother.

"Mm." Subaru whispered back, too tired to give him a proper response. Then, just as Ukyo started to take his own accessories off, Subaru mumbled, "Good night, Kyo-nii."

Ukyo turned his head over to his little brother, and smiled warmly, "Good night."

 **A/N: This was originally meant to be published for Halloween, but irl stuff got in the way sooo here I am 5 days late whoops;; But anyways! I hope someone enjoys this and do review/follow the story! I don't mind criticism either, so shoot me some if you'd like! I won't bite, I promise.**


	2. Chapter 2

**A/N: Thank you so much for being the first reviewer/follower for my story, AkariShoko! And fav as well haha xD I'll be sure to continue it until the end! That means a lot to me, especially since this is my first ever published fanfic. Now, onto the story itself!**

 **Chapter 2**

Kaname groaned, his eyes now half-lidded; his throat felt like a desert with dried up oasis's, prompting his subconscious mind to remind him he had to quench that thirst before it would worsen through the night. He then slowly sat up on the bed, rubbing both of his eyes gently to help get rid a little bit of the grogginess that lingered in them. Afterwards, he took a quick look at Yuusuke, who was sound asleep and snoring rather loudly with his mouth gaping as he covered his face and his body with his pillow and blanket respectively; it looked like he was having a good night's dream. Kaname chuckled softly at the sleeping beauty beside him, and proceeded to head outside to find something to relieve his throat.

The monk made sure to tip-toe past all the rooms, as to not wake any of his brothers up. Passing by the hallway, he continuously looked left and right for a water source, but to no avail.

He sighed; maybe drinking rain water isn't such a bad idea as Masaomi sometimes talks of it to be, it's not like he could die from some weird disease he caught while sticking his tongue out.

Just then, he looked behind him, and saw a pair of…horns? He turned his body and head around completely to make sure he wasn't seeing things.

He was tempted to scream his heart out as he saw what was on his head.

He couldn't believe what was before his eyes; didn't he take off his Halloween costume's accessories before going to bed? He decided to grip onto the tusks that were sitting atop his head, and tried to pull them out.

Instead, it hurt him as if someone was splitting him in half.

He decided to hurry over to the nearest room and wake everyone up.

* * *

Louis tossed and turned; there were loud sounds of pounding and shouts that echoed to the room, slowly taking the sleepy man away from his dream land and back into reality.

His eyes opened into a world of darkness, his body still wrapped in a thick, warm blanket and his head resting on the soft pillow. His conscious mind struggled to awaken and go investigate what pulled him out of his wondrous sleep, but instead, it urged him to just stay and ignore whatever's happening outside.

At that moment, a loud thud finally pushed Louis to get out of bed.

He first looked to his side, with no sign of Hikaru anywhere. Where could he possibly have gone at this time? It was still…night, and there were weird noises outside made by god-knows-what.

Slightly worried, Louis rushed out of the room; the sudden transition from the pitch-black room to the hallway filled with bright lights blinded him for a split second. Still, he walked forward onto the flight of stairs, seeing a gathering of people by the door.

As soon as he recovered his sight, he realized that gathering were his brothers.

"Oh! Louis, good morning." One of the men turned his head to see Louis. "Though…it's still night from the looks of it."

"Hikaru-niisan…what's happening?" Louis asked, his brow raised, but still appeared to be nonchalant like his usual self.

"Honestly…" the elder brother rubbed his head, frowning a bit. "I have no idea myself—I still can't wrap my head around all that's happened."

"Mm…?" Louis took a good look at Hikaru's hair, blinking a few times, "Hikaru-niisan, I thought you took your extensions off when we went to sleep…?"

"I could say the same for you too." Hikaru pointed towards Louis' new-grown horns and his pitchfork that he apparently hadn't noticed up until now. The devil-clad man gasped lightly as he placed his hands over his head, and looked behind his back to see small bat-like wings and a devil's tail sticking out of him. He attempted to pull at his horns, but only received a split second splitting headache in return.

"Are they…" Louis began, but Hikaru cut him off with a nod.

"I'm afraid it does go for everyone as well." Hikaru turned to his three younger brothers whom were trying so desperately to burst open the door, with the rest watching in anticipation. "Kaname was the first to wake up because he got thirsty, he soon noticed it and woke everyone up as well." He then turned back to Louis. "But you just wouldn't wake up, so we all had discussed about this earlier without you, and came to the conclusion that we became the creatures we initially dressed up themselves because of the mansion itself—I understand it sounds really weird and impossible, but considering we've scoured the mansion for a bit and there was no sign of any living thing so far, that's our only clue as for now."

Louis blinked, trying to process the information that was thrown at him in less than three minutes as he just woke up from bed.

Hikaru then pointed towards the three brothers that were still trying to break the door open, "So, as you can see, they've been trying at this for the past few minutes, but it just wouldn't budge."

"What about the windows?" Louis looked around the room, windows were scattered about endlessly from hallway to hallway.

"Didn't change a thing. Rather, it caused a few chairs and supposedly valuable objects to break, while the window itself didn't get a single scratch." Hikaru sighed at the memory of his younger red-headed brother stubbornly throwing everything he could find before he needed to be restrained by Iori and Natsume.

Louis continued to press on. "Fireplaces? If any?"

Hikaru shook his head, "Unfortunately they somehow lead to other places of the mansion with fireplaces; like a transporter of some sort." He knew all too well what happened when Tsubaki had attempted to climb in it and ended up in some basement where he screamed like there was no tomorrow; least to say was he was most probably scarred after witnessing something he described like someone had died in there.

"Hm…" Louis pondered for a minute. "What about calling the authorities to help us?"

"For some reason our phones are…missing. Every single one of them." Hikaru then pointed towards the door. "And I doubt they'd be able to get us out if even a group of grown men can't break anything beyond the walls of this mansion with heavy objects weighing more than us." He sighed once more, shoulders slumped slightly. "So in short, we're trapped."

Louis looked down onto his brown leather loafers, not sure of what to think about this situation.

* * *

Meanwhile, battle cries and consistent pushing and shoving were going on in the middle of the room.

"Natsu-nii! Put your back into it! I can feel the table slipping at the back!" Subaru shouted angrily at the wolf man that was behind his skeleton brother, almost sounding like a general yelling at his soldiers in training camp.

"I'm trying…!" Natsume's legs were getting wobblier by the minute as his hands, or rather, paws, grew clammy and sweaty from the heavy lifting and pushing.

"Try harder!" Subaru's voice cracked, clearly struggling just as much as his own older brother.

"Aaargh! I don't know how much longer I can keep on doing this!" Yuusuke was barely able to keep standing on his own two feet, not making it any better with his shaking bones.

"Just…one more time!" Subaru managed to croak out, gritting his teeth.

"1…"

The three took a few steps back.

"2…"

They all took deep breaths and got into position.

"3!"

They rammed the already worn table into the doors, with full speed ahead as fast as their legs could carry them; in fact, it felt as if they were floating for a second. Their hands were grasping tightly onto the wooden object, as if their lives depended on it.

A glimmer of hope was visible for less than a second, looking at the determined brothers' faces and their combined strength; it felt like anything was possible.

That is, until the table was at its limit and broke into segments and pieces, only scratching the surface of the door ever so lightly. All the brothers that were watching so closely and intently flew from the scene, trying to avoid the splinters that would pierce through their bodies.

Yuusuke cried out in boiling rage, with many groans following after him. That glimmer of hope dissipated from the back of their minds, with Subaru crashing down onto the floor on his knees; both from the fatigue and the hard work that went to waste.

"How the hell is that even possible?!" Fuuto yelled out what everyone's thoughts were, "We've already practically broken tons of things in this mansion and we were barely able to make a scratch?! What kind of crazy place is this?!" By this point, steam vented out through his nose.

"Maa-kun…I'm scared…will we ever get out? I miss home…" Wataru hugged onto Masaomi tightly, burying his face into his bandage-like linen cloth; the latter placed his hand onto his little brother's head, gently stroking the soft, peach pink hair under the witch's hat.

"I'm…sure we'll get out soon enough, Wataru." Masaomi didn't know whether what came out of his mouth was true or not, and desperately hoped he wasn't completely wrong; he couldn't stand seeing the rest of his brothers in such a bad atmosphere.

"I hereby call an emergency family meeting at the parlor!" Ukyo's voice thundered, startling some of his brothers.

 **A/N: Damn I'm so excited to pump everything out! I wish I could spoil what's going to happen soon in the next few chapters, but it wouldn't be as exciting, now would it? Anyways, I'm thinking of writing up the brothers conflict idol AU I've always wanted to share, if you've read it on my profile, based on the mobage Ensemble Stars; I've been so obsessed with it recently that I even created some of the logos for the units and lyrics for some of the songs haha;; so uh onto the point- what do you guys think of it? Interested in reading sth like that? Give me your thoughts! And please review, fav or follow this story as well!**


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